In the field of braking systems for the wheels of a towed vehicle, such as a trailer, there have been many systems proposed. While similar to standard braking systems on automobiles, the systems are different in that the manner of activation and release is not the same. While technical advances have been made for the automotive systems in the past, up until just recently very little change has been made in trailer braking systems. Indeed, with increased highway traffic safety regulations becoming more prevalent and stringent, improved braking for trailers is an absolute requirement. The successful system that has recently brought about the revolution in trailer brake systems is illustrated in my prior U.S. patents entitled "Trailer Brake System With Release Apparatus", U.S. Pat. Nos. 5,316,110 and 5,411,120, issued on May 31, 1994 and May 2, 1995, respectively.
Today, Null's free backing disc brake systems represented by these patents is in widespread, successful use. It is proven in extensive testing and commercial use to be highly efficient and very reliable in performance. Users have found that the performance increase in this disc brake system, especially on relatively light weight utility and boat trailers, is outstanding. As a consequence, stopping distances are significantly reduced with the Null's brake system so as to meet and exceed all federal and local requirements.
Thus, while the basic Null's brake system, including the innovative individual brake units, as used both for the master and the slave or follower units in the system, have been very successful, further improvement is desirable for meeting specific applications. While the original system was designed for relatively lightweight utility/boat trailers, there is now extremely high interest in the industry to expand the basic brake system and brake unit, as represented in the '110 and the '120 patents to accommodate larger trailers, greater axle loads and performance driving applications. In particular, fleet owners, primarily in the rental utility trailer market, are interested in a new design that provides even more efficiency in braking in the same flawless operation as before, so that the Null's system can accommodate the entire range of standard trailers, axle loading and driving conditions. That is, it is now appropriate since the basic concept is proven, to provide an improved design using the same operative principles, but which is better adapted to increased braking loads. For example, it is desirable from a commercial point of view to be able to accommodate heavier axle loads, such as 3,500 pounds GWVR, and even into the 7,000 and 10,000 pounds GWVR range. However, the need is equally critical for a system that easily withstands rapid or panic stops from the increased highway speeds of today.